European Crane Fly

The European Crane Fly Tipula paludosa (Fr. cousin or Tipule des prairies) is the best known of hundreds of crane flies in the Tipulidae family of flies. They resemble gigantic mosquitoes with enormously long legs, and indeed are often mistaken for mozzies. But they lack the mouthparts to bite and are entirely inoffensive. Their larvae, known as leatherjackets, are capable of doing considerable damage to lawns, sports fields, arable crops and seedlings.

 

A female European Crane Fly Tipula paludosa, resting on the exterior wall of our house near the back door.

The scientific name means something like 'abundant wetland spider'.

They are around 20 mm long, with exceptionally long hind legs. Their heads are weird and elongated and their grey thorax has dark lengthwise stripes. The wings have a very slight cloudiness and a brown leading edge.

 

Close up of the head.

The European Crane Fly closely resembles the Marsh Crane Fly T. oleracea (Fr. Tipule potagère). They are a nightmare to separate if you are trying to accurately identify them, especially from photos. My colleagues and I spent several hours to-ing and fro-ing on Facebook discussing my photos. In the end we settled on T. paludosa because of the colour of the antennae ie they are reddish on the first two segments, then grey. Importantly, and how most are identified, T. paludosa has 13 antennal segments and T. oleracea has 14 -- but you will go cross-eyed counting them and the segment at the tip is easy to miss in a photo. Female T. paludosa have wings that are shorter than their abdomens, whereas T. oleracea's wings are longer. But because they always rest with their wings spread at an angle it is very hard to judge this character. There are supposed to be subtle differences in the wing venation too, but I'm damned if I can see it. Likewise in the shape of the eyes - but to see that you have to have a photo from underneath and face on. Of course, if you really have to know which species you have you must take a specimen and look at the genitalia under magnification. Crane flies are notoriously difficult and fragile, so very few people take the time.

The larvae are 3-4 cm long maggots known in French as 'vers gris' (grey worms) on account of their dirt grey colour. They are squishy but tough, hence their English name of leatherjackets. They don't have legs but shift along by contracting and extending lengthwise in quite an animated way. They live underground and eat the roots of plants.

 

Female European Crane Fly resting on the outside of our house last week.

Adult European Crane Flies live for about a fortnight. They start appearing in June and can be seen until October. They tend to fly morning and evening, and favour damp habitats. Once the weather cools down in autumn they become more visible as they seek shelter, often entering houses. A female will lay several hundred black eggs, in batches of 5 or 6, as she flies or wherever she pauses to rest. The eggs will hatch in 15 days and the tiny larvae will go underground for the winter. In June they will pupate underground, finally emerging as adults in 2 or 3 weeks. The larvae are quite an important source of food for birds and amphibians.

 European Crane Flies' natural distribution is throughout Europe and they have been accidentally introduced to North America.